[release plugin] error when a file already exists in SVN

Hi Rob:
We should handle this case:
[INFO]
------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO]
------------------------------------------------------------------------
[INFO] Total time: 04:12 min
[INFO] Finished at: 2018-06-09T11:07:28-06:00
[INFO]
------------------------------------------------------------------------
[ERROR] Failed to execute goal
org.apache.commons:commons-release-plugin:1.2:stage-distributions
(stage-distributions) on project commons-text: Adding dist files failed:
svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.tar.gz'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.tar.gz.asc'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.tar.gz.md5'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.tar.gz.sha1'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.zip'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.zip.asc'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.zip.md5'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\binaries\commons-text-1.4-bin.zip.sha1'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.tar.gz'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.tar.gz.asc'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.tar.gz.md5'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.tar.gz.sha1'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.zip'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.zip.asc'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.zip.md5'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\source\commons-text-1.4-src.zip.sha1'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\site.zip'
is already under version control
[ERROR] svn: warning: W150002:
'C:\vcs\git\apache\commons\commons-text\target\commons-release-plugin\scm\RELEASE-NOTES.txt'
is already under version control
[ERROR] svn: E200009: Could not add all targets because some targets are
already versioned
[ERROR] svn: E200009: Illegal target for the requested operation
[ERROR]
Thank you,
Gary